Hi Andrey,
For bulk materials a Monkhorst Pack grid of 21^3 is sufficient to stop
the eps(w) for a constant optical mesh (Depending on the system).
Whereas an optical mesh grid of 41^3 vs 45^3 still shifts eps(w) around
a bit for constant Monkhorst Pack grid. The broadening also affects what
can be considered converged. I generally keep the optical broadening
very low as you can always broaden more but never less. However, this
does mean an optical mesh of 45 isn't sufficient for convergence. Hope
this helped.
Cheers,
Marty
---------------------
Martin Blaber
Institute for Nanoscale Technology
Dept. of Physics and Advanced Materials
University of Technology, Sydney
[EMAIL PROTECTED] wrote:
Hi all,
I am trying to find some description of the Optical.Mesh variable
which is more detailed than the one given in the Siesta manual.
Some of my colleagues insist that the convergence of optical properties
eps(w) with respect to the number of k-points in the integral wrt
k over the BZ has to be shown not based on the vaues in the Optical.Mesh but rather based on the values of MonkhorstPack_grid. How can I prove the opposite, i.e. that BZ sampling grid refinement for optical property
calculations must be based on the Optical.Mesh variable?
Thanks,
Andrey Semichaevsky,
CEMOS, ECE Dept., UMass Lowell
